Configuration inconsistency identification between storage virtual machines

ABSTRACT

One or more techniques and/or systems are provided for identifying configuration inconsistencies between storage virtual machines across storage clusters. For example, a first storage cluster and a second storage cluster may be configured according to a disaster recovery relationship where user data and configuration data of the first storage cluster are replicated to the second storage cluster so that the second storage cluster can takeover for the first storage cluster in the event a disaster occurs at the first storage cluster. Because replication of configuration data (e.g., a name and size of a volume, a backup policy, etc.) may fail for various reasons, configuration of the first storage cluster is compared to configuration of the second storage cluster to identify a configuration difference (e.g., a new size of the volume at the first storage cluster may have failed to be replicated to a replicated volume at the second storage cluster).

BACKGROUND

A storage network environment may comprise one or more storage clustersof storage controllers (e.g., nodes) configured to provide clients withaccess to user data stored within storage devices. For example, a firststorage cluster may comprise a first storage controller configured toprovide clients with access to user data stored within a first storagedevice. A second storage cluster may be configured according to adisaster recovery configuration with respect to the first storagecluster, such that user data (e.g., user files, applications, etc.) andconfiguration data (e.g., a name and size of a volume, a replicationpolicy, a user access policy, a network interface configuration, an IPaddress, and/or other back-end configuration data of the storage networkenvironment) are replicated from the first storage cluster to the secondstorage cluster. In this way, when a disaster occurs at the firststorage cluster and clients are unable to access user data within thefirst storage device because the first storage controller may beunavailable or may have failed from the disaster, a second storagecontroller of the second storage cluster may provide clients withfailover access to replicated user data that was replicated from thefirst storage device to a second storage device accessible to the secondstorage controller. When the first storage cluster recovers from thedisaster, the second storage cluster may switch back to the firststorage cluster such that the first storage controller provides clientswith access to user data from the first storage device. In this way,user data and configuration data may be backed up between storageclusters for disaster recovery.

Synchronization of configuration data from the first storage cluster tothe second storage cluster may fail for various reasons. In an example,configuration mirroring data (e.g., a volume rename operation for avolume at the first storage cluster may be mirrored as the configurationmirroring data to the second storage cluster to rename a correspondingreplicated volume to match a new name of the volume) that is to be sentfrom the first storage cluster to the second storage cluster may fail tobe transmitted. In another example, the configuration mirroring data mayfail to be applied at the second storage cluster (e.g., configurationdata of a first storage virtual machine of the first storage cluster mayfail to be applied to a second storage virtual machine, of the secondstorage cluster, that is configured as a backup storage virtual machinefor the first storage virtual machine). In another example, theconfiguration mirroring data may fail to be recorded at the secondstorage cluster. Thus, a client may be unaware of the inconsistency inconfiguration data between the storage clusters (e.g., a volume namechange or resize operation may modify volume name configuration data orvolume size configuration data at the first storage cluster, but afailure to propagate such configuration data to the second storagecluster may result in the second storage cluster comprising a mirroredvolume with a stale/incorrect name or size), which may result in errors(e.g., an error when attempting to access a replicated storage objecthaving a stale out-of-date internet protocol (IP) address), securityissues such as unauthorized access (e.g., a stale out-of-date useraccess policy may still grant a user with access to replicated user datathat the user is now not supposed to access), an inability for clientsto access to client data (e.g., a user may be unable to access areplicated volume having a stale out-of-date volume name), and/or otherfailures.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a component block diagram illustrating an example clusterednetwork in accordance with one or more of the provisions set forthherein.

FIG. 2 is a component block diagram illustrating an example data storagesystem in accordance with one or more of the provisions set forthherein.

FIG. 3 is a flow chart illustrating an exemplary method of identifyingconfiguration inconsistencies between storage virtual machines acrossstorage clusters.

FIG. 4A is a component block diagram illustrating an exemplary systemfor identifying configuration inconsistencies between storage virtualmachines across storage clusters.

FIG. 4B is a component block diagram illustrating an exemplary systemfor identifying configuration inconsistencies between storage virtualmachines across storage clusters, where user data and configuration datais replicated from a first storage virtual machine to a second storagevirtual machine.

FIG. 4C is a component block diagram illustrating an exemplary systemfor identifying configuration inconsistencies between storage virtualmachines across storage clusters, where a first configuration of a firststorage virtual machine is compared with a second configuration of asecond storage virtual machine.

FIG. 5A is a component block diagram illustrating an exemplary systemfor identifying configuration inconsistencies between storage virtualmachines across storage clusters.

FIG. 5B is a component block diagram illustrating an exemplary systemfor identifying configuration inconsistencies between storage virtualmachines across storage clusters, where configuration mirroring datafails to be transferred from a first storage cluster to a second storagecluster, resulting in a configuration difference.

FIG. 6A is a component block diagram illustrating an exemplary systemfor identifying configuration inconsistencies between storage virtualmachines across storage clusters.

FIG. 6B is a component block diagram illustrating an exemplary systemfor identifying configuration inconsistencies between storage virtualmachines across storage clusters, where configuration mirroring datafails to be applied to a replicated user access policy, resulting in aconfiguration difference.

FIG. 7A is a component block diagram illustrating an exemplary systemfor identifying configuration inconsistencies between storage virtualmachines across storage clusters.

FIG. 7B is a component block diagram illustrating an exemplary systemfor identifying configuration inconsistencies between storage virtualmachines across storage clusters, where configuration mirroring datafails to be recorded for a replicated IP address, resulting in aconfiguration difference.

FIG. 8 is an example of a computer readable medium in accordance withone or more of the provisions set forth herein.

DETAILED DESCRIPTION

Some examples of the claimed subject matter are now described withreference to the drawings, where like reference numerals are generallyused to refer to like elements throughout. In the following description,for purposes of explanation, numerous specific details are set forth inorder to provide an understanding of the claimed subject matter. It maybe evident, however, that the claimed subject matter may be practicedwithout these specific details. Nothing in this detailed description isadmitted as prior art.

One or more systems and/or techniques for identifying configurationinconsistencies between storage virtual machines across storage clustersare provided. A first storage cluster and a second storage cluster maybe configured according to a disaster recovery configuration (e.g., asynchronous or an asynchronous disaster recovery mirroring partnership),such that the user data and configuration data of the first storagecluster may be replicated/mirrored from the first storage cluster to thesecond storage cluster so that the second storage cluster may providefailover access to replicated user data in the event a disaster occursat the first storage cluster. Similarly, user data and configurationdata of the second storage cluster may be replicated/mirrored from thesecond storage cluster to the first storage cluster so that the firststorage cluster may provide failover access to replicated user data inthe event a disaster occurs at the second storage cluster. Failure toreplicate configuration data may result in inconsistencies (e.g.,inconsistent IP addresses, network interfaces, volume names, volumesizes, etc.) that may hinder a failover storage cluster's ability toprovide clients with access to replicated user data in the event of adisaster of a primary storage cluster (e.g., a user may be unable toaccess a replicated volume having an stale out-of-date name).Accordingly, as provided herein, configuration data of a first storagevirtual machine, within the first storage cluster, and a second storagevirtual machine, within the second storage cluster and having areplication relationship with the first storage virtual machine, may becompared to identify configuration differences. In this way, clients maybe notified of configuration differences so that corrective action maybe taken.

To provide context for configuration inconsistency identification, FIG.1 illustrates an embodiment of a clustered network environment 100 or anetwork storage environment. It may be appreciated, however, that thetechniques, etc. described herein may be implemented within theclustered network environment 100, a non-cluster network environment,and/or a variety of other computing environments, such as a desktopcomputing environment. That is, the instant disclosure, including thescope of the appended claims, is not meant to be limited to the examplesprovided herein. It will be appreciated that where the same or similarcomponents, elements, features, items, modules, etc. are illustrated inlater figures but were previously discussed with regard to priorfigures, that a similar (e.g., redundant) discussion of the same may beomitted when describing the subsequent figures (e.g., for purposes ofsimplicity and ease of understanding).

FIG. 1 is a block diagram illustrating an example clustered networkenvironment 100 that may implement at least some embodiments of thetechniques and/or systems described herein. The example environment 100comprises data storage systems or storage sites 102 and 104 that arecoupled over a cluster fabric 106, such as a computing network embodiedas a private Infiniband, Fibre Channel (FC), or Ethernet networkfacilitating communication between the storage systems 102 and 104 (andone or more modules, component, etc. therein, such as, nodes 116 and118, for example). It will be appreciated that while two data storagesystems 102 and 104 and two nodes 116 and 118 are illustrated in FIG. 1,that any suitable number of such components is contemplated. In anexample, nodes 116, 118 comprise storage controllers (e.g., node 116 maycomprise a primary or local storage controller and node 118 may comprisea secondary or remote storage controller) that provide client devices,such as host devices 108, 110, with access to data stored within datastorage devices 128, 130. Similarly, unless specifically providedotherwise herein, the same is true for other modules, elements,features, items, etc. referenced herein and/or illustrated in theaccompanying drawings. That is, a particular number of components,modules, elements, features, items, etc. disclosed herein is not meantto be interpreted in a limiting manner.

It will be further appreciated that clustered networks are not limitedto any particular geographic areas and can be clustered locally and/orremotely. Thus, in one embodiment a clustered network can be distributedover a plurality of storage systems and/or nodes located in a pluralityof geographic locations; while in another embodiment a clustered networkcan include data storage systems (e.g., 102, 104) residing in a samegeographic location (e.g., in a single onsite rack of data storagedevices).

In the illustrated example, one or more host devices 108, 110 which maycomprise, for example, client devices, personal computers (PCs),computing devices used for storage (e.g., storage servers), and othercomputers or peripheral devices (e.g., printers), are coupled to therespective data storage systems 102, 104 by storage network connections112, 114. Network connection may comprise a local area network (LAN) orwide area network (WAN), for example, that utilizes Network AttachedStorage (NAS) protocols, such as a Common Internet File System (CIFS)protocol or a Network File System (NFS) protocol to exchange datapackets. Illustratively, the host devices 108, 110 may begeneral-purpose computers running applications, and may interact withthe data storage systems 102, 104 using a client/server model forexchange of information. That is, the host device may request data fromthe data storage system (e.g., data on a storage device managed by anetwork storage control configured to process I/O commands issued by thehost device for the storage device), and the data storage system mayreturn results of the request to the host device via one or more networkconnections 112, 114.

The nodes 116, 118 on clustered data storage systems 102, 104 cancomprise network or host nodes that are interconnected as a cluster toprovide data storage and management services, such as to an enterprisehaving remote locations, cloud storage (e.g., a storage endpoint may bestored within a data cloud), etc., for example. Such a node in a datastorage and management network cluster environment 100 can be a deviceattached to the network as a connection point, redistribution point orcommunication endpoint, for example. A node may be capable of sending,receiving, and/or forwarding information over a network communicationschannel, and could comprise any device that meets any or all of thesecriteria. One example of a node may be a data storage and managementserver attached to a network, where the server can comprise a generalpurpose computer or a computing device particularly configured tooperate as a server in a data storage and management system.

In an example, a first cluster of nodes such as the nodes 116, 118(e.g., a first set of storage controllers configured to provide accessto a first storage aggregate comprising a first logical grouping of oneor more storage devices) may be located on a first storage site. Asecond cluster of nodes, not illustrated, may be located at a secondstorage site (e.g., a second set of storage controllers configured toprovide access to a second storage aggregate comprising a second logicalgrouping of one or more storage devices). The first cluster of nodes andthe second cluster of nodes may be configured according to a disasterrecovery configuration where a surviving cluster of nodes providesswitchover access to storage devices of a disaster cluster of nodes inthe event a disaster occurs at a disaster storage site comprising thedisaster cluster of nodes (e.g., the first cluster of nodes providesclient devices with switchover data access to storage devices of thesecond storage aggregate in the event a disaster occurs at the secondstorage site).

As illustrated in the exemplary environment 100, nodes 116, 118 cancomprise various functional components that coordinate to providedistributed storage architecture for the cluster. For example, the nodescan comprise a network module 120, 122 and a data module 124, 126.Network modules 120, 122 can be configured to allow the nodes 116, 118(e.g., network storage controllers) to connect with host devices 108,110 over the network connections 112, 114, for example, allowing thehost devices 108, 110 to access data stored in the distributed storagesystem. Further, the network modules 120, 122 can provide connectionswith one or more other components through the cluster fabric 106. Forexample, in FIG. 1, a first network module 120 of first node 116 canaccess a second data storage device 130 by sending a request through asecond data module 126 of a second node 118.

Data modules 124, 126 can be configured to connect one or more datastorage devices 128, 130, such as disks or arrays of disks, flashmemory, or some other form of data storage, to the nodes 116, 118. Thenodes 116, 118 can be interconnected by the cluster fabric 106, forexample, allowing respective nodes in the cluster to access data on datastorage devices 128, 130 connected to different nodes in the cluster.Often, data modules 124, 126 communicate with the data storage devices128, 130 according to a storage area network (SAN) protocol, such asSmall Computer System Interface (SCSI) or Fiber Channel Protocol (FCP),for example. Thus, as seen from an operating system on a node 116, 118,the data storage devices 128, 130 can appear as locally attached to theoperating system. In this manner, different nodes 116, 118, etc. mayaccess data blocks through the operating system, rather than expresslyrequesting abstract files.

It should be appreciated that, while the example embodiment 100illustrates an equal number of network and data modules, otherembodiments may comprise a differing number of these modules. Forexample, there may be a plurality of network and data modulesinterconnected in a cluster that does not have a one-to-onecorrespondence between the network and data modules. That is, differentnodes can have a different number of network and data modules, and thesame node can have a different number of network modules than datamodules.

Further, a host device 108, 110 can be networked with the nodes 116, 118in the cluster, over the networking connections 112, 114. As an example,respective host devices 108, 110 that are networked to a cluster mayrequest services (e.g., exchanging of information in the form of datapackets) of a node 116, 118 in the cluster, and the node 116, 118 canreturn results of the requested services to the host devices 108, 110.In one embodiment, the host devices 108, 110 can exchange informationwith the network modules 120, 122 residing in the nodes (e.g., networkhosts) 116, 118 in the data storage systems 102, 104.

In one embodiment, the data storage devices 128, 130 comprise volumes132, which is an implementation of storage of information onto diskdrives or disk arrays or other storage (e.g., flash) as a file-systemfor data, for example. Volumes can span a portion of a disk, acollection of disks, or portions of disks, for example, and typicallydefine an overall logical arrangement of file storage on disk space inthe storage system. In one embodiment a volume can comprise stored dataas one or more files that reside in a hierarchical directory structurewithin the volume.

Volumes are typically configured in formats that may be associated withparticular storage systems, and respective volume formats typicallycomprise features that provide functionality to the volumes, such asproviding an ability for volumes to form clusters. For example, where afirst storage system may utilize a first format for their volumes, asecond storage system may utilize a second format for their volumes.

In the example environment 100, the host devices 108, 110 can utilizethe data storage systems 102, 104 to store and retrieve data from thevolumes 132. In this embodiment, for example, the host device 108 cansend data packets to the network module 120 in the node 116 within datastorage system 102. The node 116 can forward the data to the datastorage device 128 using the data module 124, where the data storagedevice 128 comprises volume 132A. In this way, in this example, the hostdevice can access the storage volume 132A, to store and/or retrievedata, using the data storage system 102 connected by the networkconnection 112. Further, in this embodiment, the host device 110 canexchange data with the network module 122 in the host 118 within thedata storage system 104 (e.g., which may be remote from the data storagesystem 102). The host 118 can forward the data to the data storagedevice 130 using the data module 126, thereby accessing volume 132Bassociated with the data storage device 130.

It may be appreciated that configuration inconsistency identificationmay be implemented within the clustered network environment 100. Forexample, a configuration comparison component may be implemented for thenode 116 and/or the node 118. The configuration comparison component maybe configured to identify configuration inconsistencies between the node116 and the node 118, such as where the node 116 is hosted within afirst storage cluster and the node 118 is hosted within a second storagecluster that is a disaster recovery partner for the first storagecluster.

FIG. 2 is an illustrative example of a data storage system 200 (e.g.,102, 104 in FIG. 1), providing further detail of an embodiment ofcomponents that may implement one or more of the techniques and/orsystems described herein. The example data storage system 200 comprisesa node 202 (e.g., host nodes 116, 118 in FIG. 1), and a data storagedevice 234 (e.g., data storage devices 128, 130 in FIG. 1). The node 202may be a general purpose computer, for example, or some other computingdevice particularly configured to operate as a storage server. A hostdevice 205 (e.g., 108, 110 in FIG. 1) can be connected to the node 202over a network 216, for example, to provides access to files and/orother data stored on the data storage device 234. In an example, thenode 202 comprises a storage controller that provides client devices,such as the host device 205, with access to data stored within datastorage device 234.

The data storage device 234 can comprise mass storage devices, such asdisks 224, 226, 228 of a disk array 218, 220, 222. It will beappreciated that the techniques and systems, described herein, are notlimited by the example embodiment. For example, disks 224, 226, 228 maycomprise any type of mass storage devices, including but not limited tomagnetic disk drives, flash memory, and any other similar media adaptedto store information, including, for example, data (D) and/or parity (P)information.

The node 202 comprises one or more processors 204, a memory 206, anetwork adapter 210, a cluster access adapter 212, and a storage adapter214 interconnected by a system bus 242. The storage system 200 alsoincludes an operating system 208 installed in the memory 206 of the node202 that can, for example, implement a Redundant Array of Independent(or Inexpensive) Disks (RAID) optimization technique to optimize areconstruction process of data of a failed disk in an array.

The operating system 208 can also manage communications for the datastorage system, and communications between other data storage systemsthat may be in a clustered network, such as attached to a cluster fabric215 (e.g., 106 in FIG. 1). Thus, the node 202, such as a network storagecontroller, can respond to host device requests to manage data on thedata storage device 234 (e.g., or additional clustered devices) inaccordance with these host device requests. The operating system 208 canoften establish one or more file systems on the data storage system 200,where a file system can include software code and data structures thatimplement a persistent hierarchical namespace of files and directories,for example. As an example, when a new data storage device (not shown)is added to a clustered network system, the operating system 208 isinformed where, in an existing directory tree, new files associated withthe new data storage device are to be stored. This is often referred toas “mounting” a file system.

In the example data storage system 200, memory 206 can include storagelocations that are addressable by the processors 204 and adapters 210,212, 214 for storing related software application code and datastructures. The processors 204 and adapters 210, 212, 214 may, forexample, include processing elements and/or logic circuitry configuredto execute the software code and manipulate the data structures. Theoperating system 208, portions of which are typically resident in thememory 206 and executed by the processing elements, functionallyorganizes the storage system by, among other things, invoking storageoperations in support of a file service implemented by the storagesystem. It will be apparent to those skilled in the art that otherprocessing and memory mechanisms, including various computer readablemedia, may be used for storing and/or executing application instructionspertaining to the techniques described herein. For example, theoperating system can also utilize one or more control files (not shown)to aid in the provisioning of virtual machines.

The network adapter 210 includes the mechanical, electrical andsignaling circuitry needed to connect the data storage system 200 to ahost device 205 over a computer network 216, which may comprise, amongother things, a point-to-point connection or a shared medium, such as alocal area network. The host device 205 (e.g., 108, 110 of FIG. 1) maybe a general-purpose computer configured to execute applications. Asdescribed above, the host device 205 may interact with the data storagesystem 200 in accordance with a client/host model of informationdelivery.

The storage adapter 214 cooperates with the operating system 208executing on the node 202 to access information requested by the hostdevice 205 (e.g., access data on a storage device managed by a networkstorage controller). The information may be stored on any type ofattached array of writeable media such as magnetic disk drives, flashmemory, and/or any other similar media adapted to store information. Inthe example data storage system 200, the information can be stored indata blocks on the disks 224, 226, 228. The storage adapter 214 caninclude input/output (I/O) interface circuitry that couples to the disksover an I/O interconnect arrangement, such as a storage area network(SAN) protocol (e.g., Small Computer System Interface (SCSI), iSCSI,hyperSCSI, Fiber Channel Protocol (FCP)). The information is retrievedby the storage adapter 214 and, if necessary, processed by the one ormore processors 204 (or the storage adapter 214 itself) prior to beingforwarded over the system bus 242 to the network adapter 210 (and/or thecluster access adapter 212 if sending to another node in the cluster)where the information is formatted into a data packet and returned tothe host device 205 over the network connection 216 (and/or returned toanother node attached to the cluster over the cluster fabric 215).

In one embodiment, storage of information on arrays 218, 220, 222 can beimplemented as one or more storage “volumes” 230, 232 that are comprisedof a cluster of disks 224, 226, 228 defining an overall logicalarrangement of disk space. The disks 224, 226, 228 that comprise one ormore volumes are typically organized as one or more groups of RAIDs. Asan example, volume 230 comprises an aggregate of disk arrays 218 and220, which comprise the cluster of disks 224 and 226.

In one embodiment, to facilitate access to disks 224, 226, 228, theoperating system 208 may implement a file system (e.g., write anywherefile system) that logically organizes the information as a hierarchicalstructure of directories and files on the disks. In this embodiment,respective files may be implemented as a set of disk blocks configuredto store information, whereas directories may be implemented asspecially formatted files in which information about other files anddirectories are stored.

Whatever the underlying physical configuration within this data storagesystem 200, data can be stored as files within physical and/or virtualvolumes, which can be associated with respective volume identifiers,such as file system identifiers (FSIDs), which can be 32-bits in lengthin one example.

A physical volume corresponds to at least a portion of physical storagedevices whose address, addressable space, location, etc. doesn't change,such as at least some of one or more data storage devices 234 (e.g., aRedundant Array of Independent (or Inexpensive) Disks (RAID system)).Typically the location of the physical volume doesn't change in that the(range of) address(es) used to access it generally remains constant.

A virtual volume, in contrast, is stored over an aggregate of disparateportions of different physical storage devices. The virtual volume maybe a collection of different available portions of different physicalstorage device locations, such as some available space from each of thedisks 224, 226, and/or 228. It will be appreciated that since a virtualvolume is not “tied” to any one particular storage device, a virtualvolume can be said to include a layer of abstraction or virtualization,which allows it to be resized and/or flexible in some regards.

Further, a virtual volume can include one or more logical unit numbers(LUNs) 238, directories 236, Qtrees 235, and files 240. Among otherthings, these features, but more particularly LUNS, allow the disparatememory locations within which data is stored to be identified, forexample, and grouped as data storage unit. As such, the LUNs 238 may becharacterized as constituting a virtual disk or drive upon which datawithin the virtual volume is stored within the aggregate. For example,LUNs are often referred to as virtual drives, such that they emulate ahard drive from a general purpose computer, while they actually comprisedata blocks stored in various parts of a volume.

In one embodiment, one or more data storage devices 234 can have one ormore physical ports, wherein each physical port can be assigned a targetaddress (e.g., SCSI target address). To represent respective volumesstored on a data storage device, a target address on the data storagedevice can be used to identify one or more LUNs 238. Thus, for example,when the node 202 connects to a volume 230, 232 through the storageadapter 214, a connection between the node 202 and the one or more LUNs238 underlying the volume is created.

In one embodiment, respective target addresses can identify multipleLUNs, such that a target address can represent multiple volumes. The I/Ointerface, which can be implemented as circuitry and/or software in thestorage adapter 214 or as executable code residing in memory 206 andexecuted by the processors 204, for example, can connect to volume 230by using one or more addresses that identify the LUNs 238.

It may be appreciated that configuration inconsistency identificationmay be implemented for the data storage system 200. For example, aconfiguration comparison component may be implemented for the node 202.The configuration comparison component may be configured to identifyconfiguration inconsistencies between the node 202 and a second node,such as where the node 202 is hosted within a first storage cluster andthe second node is hosted within a second storage cluster that is adisaster recovery partner for the first storage cluster.

One embodiment of identifying configuration inconsistencies betweenstorage virtual machines across storage clusters is illustrated by anexemplary method 300 of FIG. 3. A first storage cluster and a secondstorage cluster may be configured according to a disaster recoveryconfiguration where user data and configuration data (e.g., volumeinformation, LUN information, snapshot policy information, networkinterface information, routing route information, IP information,storage object information, user access policy information, storageconfiguration policy information, and/or other configuration andmetadata associated with how storage is structured and managed bystorage controllers and/or other storage applications and components) issynchronously or asynchronously replicated from the first storagecluster to the second storage cluster. That is, a first storagecontroller of the first storage cluster may provide primary clientaccess to user data stored within a first storage virtual machine withinthe first storage cluster. The user data and configuration data of thefirst storage virtual machine may be replicated to the second storagecluster, such as into a second storage virtual machine, so that a secondstorage controller may provide failover client access to replicated userdata within the second storage virtual machine in the event a disasteroccurs at the first storage cluster. Responsive to the first storagecluster recovering from the disaster, the second storage cluster mayswitch back control to the first storage cluster for providing primaryclient access to user data from the first storage virtual machine.

Unfortunately, replication of the configuration data from the firststorage virtual machine to the second storage virtual machine may failfor various reasons, such as a failure to transmit, apply, commit,and/or record, which may create inconsistencies between the storagevirtual machines (e.g., if a name of a volume is changed on the firststorage virtual machine, but the name is not replicated to a replicatedvolume on the second storage virtual machine, then in the event afailover to the second storage virtual machine occurs, a user may beunable to access the replicated volume having a stale out-of-date namebecause of the name difference). Accordingly, as provided herein,configuration between the first storage virtual machine and the secondstorage virtual machine is compared to identify configurationdifferences.

At 302, the first storage virtual machine may be evaluated to identify afirst configuration of the first storage virtual machine. For example, aLUN, within the first storage virtual machine, may have a LUN name“LUN_USERA”, a size of 500 GB, is accessible through an IP address111.222.444.55, has a snapshot policy of creating a snapshot every 4days, and has other configuration properties. The first configurationmay reflect a current state of configuration data of the first storagevirtual machine, such as a current state of LUN configuration data. At304, the second storage virtual machine may be evaluated to identify asecond configuration of a second storage virtual machine. For example, areplicated LUN within the second storage virtual machine, that is areplication/mirroring of the LUN within the first storage virtualmachine, may have the LUN name “LUN_USERA”, a size of 300 GB (e.g., aresize of the LUN from 300 GB to 500 GB, at the first storage virtualmachine, may have failed to replicate to the replicated LUN, and thusthe replicated LUN may have a stale out-of-date size), is accessiblethrough the IP address 111.222.444.55, has the snapshot policy ofcreating a snapshot every 4 days, and has other configurationproperties.

At 306, the first configuration and the second configuration may becompared to determine whether there is a configuration differencebetween the first storage virtual machine and the second storage virtualmachine. In an example, the comparison may be performed in real-timeduring operation of the first storage cluster and the second storagecluster (e.g., during replication of user data and/or configuration datafrom the first storage cluster to the second storage cluster). In anexample, volume information, LUN information, snapshot policies, networkinterfaces, routing routes, IP information, storage object information,user access policies, storage configuration policies, and/or otherconfiguration data may be compared between the first configuration andthe second configuration. For example, a LUN size configurationdifference may be detected based upon the LUN, within the first storagevirtual machine, having the most up-to-date 500 GB size and thereplicated LUN, within the second storage virtual machine, having thestale out-of-date 300 GB size.

At 308, responsive to determining the configuration difference, anotification of the configuration difference may be provided. Forexample, the LUN size configuration difference may be detailed through astorage administrator user interface, a storage administration website,an email, a client interface, etc. In an example, the notification mayspecify that the configuration difference resulted from a failure totransfer configuration mirroring data (e.g., a resize operationperformed upon the LUN within the first storage virtual machine) fromthe first storage cluster to the second storage cluster for applying tothe second storage virtual machine. In an example, the notification mayspecify that the configuration difference resulted from a failure toapply the configuration mirroring data to the second storage virtualmachine. In an example, the notification may specify that theconfiguration difference resulted from a failure to record theconfiguration mirroring data for applying to the second storage virtualmachine. In this way, a client or storage administrator may be notifiedof the configuration difference, such as a notification of a differencebetween volume information, snapshot policy information, networkinterface information, routing route information, IP information,storage object information, user access policy information, storageconfiguration policy information, etc.

FIGS. 4A-4C illustrate examples of a system 400, comprising aconfiguration comparison component 406, for identifying configurationinconsistencies between storage virtual machine across storage clusters.A first storage cluster 402 and a second storage cluster 404 may beconfigured according to a disaster recovery configuration, where changesto user data and configuration data managed by the first storage cluster402 are backed up to the second storage cluster 404, and changes to userdata and configuration data managed by the second storage cluster 404are backed up to the first storage cluster 402. For example, user data422 and configuration data 424 may be replicated from a first storagevirtual machine of the first storage cluster 402 to a second storagevirtual machine of the second storage cluster 404, as illustrated inFIG. 4A. The configuration data 424 may correspond to volume information408, snapshot policy information 410, IP information 412, user accesspolicy information 414, storage object information 416, storageconfiguration policy information 418, routing routes information 420,and/or other configuration information of the first storage virtualmachine that may be replicated to the second storage virtual machine asreplicated volume information 426, replicated snapshot policyinformation 428, replicated IP information 430, replicated user accesspolicy information 432, replicated storage object information 434,replicated storage configuration policy information 436, replicatedrouting routes information 438, etc.

FIG. 4B illustrates a resize operation being performed upon a volume (A)of the first storage virtual machine, resulting in a new size 452 of 5GB being configured through the volume information 408 for the volume(A). The new size 452 of 5 GB may be replicated as configurationmirroring data 454, from the first storage cluster 402 to the secondstorage cluster 404, to apply to a replicated volume (A), associatedwith the replicated volume information 426, of the second storagevirtual machine.

FIG. 4C illustrates an example where the configuration mirroring data454 is successfully applied to the replicated volume (A), resulting in areplicated new size 460 of 5 GB being configured through the replicatedvolume information 426 for the replicated volume (A). The configurationcomparison component 406 may obtain, such as in real-time, a firstconfiguration 462 of the first storage virtual machine of the firststorage cluster 402 and a second configuration 464 of the second storagevirtual machine of the second storage cluster 404. The configurationcomparison component 406 may compare the first configuration 462 and thesecond configuration 464 to determine that no configuration differencesexist (e.g., the new size 452 of 5 GB of the volume (A) on the firststorage virtual machine was successfully replicated to the replicatedvolume (A) on the second storage virtual machine).

FIGS. 5A-5B illustrate examples of a system 500, comprising aconfiguration comparison component 514 (e.g., hosted within a firststorage cluster 502, a second storage cluster 508, or another locationor computing device such as an administrator laptop or storage server),for identifying configuration inconsistencies between storage virtualmachine across storage clusters. The first storage cluster 502 and thesecond storage cluster 508 may be configured according to a disasterrecovery configuration, where changes to user data and configurationdata managed by the first storage cluster 502 are backed up to thesecond storage cluster 508 and changes to user data and configurationdata managed by the second storage cluster 508 are backed up to thefirst storage cluster 502. For example, user data (e.g., user datawithin a LUN 506) and configuration data (e.g., a name “LUN_ABC” and asize of 3 GB of the LUN 506) may be replicated from a first storagevirtual machine 504 of the first storage cluster 502 to a second storagevirtual machine 510 of the second storage cluster 508 (e.g., to areplicated LUN 512 having the name “LUN_ABC” and the size of 3 GB), asillustrated in FIG. 5A.

FIG. 5B illustrates a LUN rename operation being applied to the LUN 506within the first storage virtual machine 504. For example, the LUN 506may be renamed from the name “LUN_ABC” to a new name “LUN_123”. Anattempt may be made to replicate/mirror the LUN rename operation, asconfiguration mirroring data, from the first storage cluster 502 to thesecond storage cluster 508 for application to the replicated LUN 512.However, transfer of the configuration mirroring data may fail 530, andthus the replicated LUN 512 may have a stale out-of-date name of“LUN_ABC” instead of the new name “LUN _123”. Thus, if a failover occursfrom the first storage cluster 502 to the second storage cluster 508 dueto a disaster at the first storage cluster 502, the replicated LUN 512may be inaccessible to clients using the new name “LUN_123”.

The configuration comparison component 514 may obtain firstconfiguration 532, corresponding to a current state of configurationdata for the first storage virtual machine 504 such as the LUN 506, fromthe first storage cluster 502. The configuration comparison component514 may obtain second configuration 534, corresponding to a currentstate of configuration data for the second storage virtual machine 510such as the replicated LUN 512, from the second storage cluster 508. Theconfiguration comparison component 514 may compare the firstconfiguration 532 and the second configuration 534 to determine a LUNname configuration difference between the LUN 506 and the replicated LUN512 due to the transfer failure 530 of the configuration mirroring data.The configuration comparison component 514 may provide a notification536 of the LUN name configuration difference, such as through a storageuser interface 536.

FIGS. 6A-6B illustrate examples of a system 600, comprising aconfiguration comparison component 614 (e.g., hosted within a firststorage cluster 602, a second storage cluster 608, or another locationor computing device such as an administrator laptop or storage server),for identifying configuration inconsistencies between storage virtualmachine across storage clusters. The first storage cluster 602 and thesecond storage cluster 608 may be configured according to a disasterrecovery configuration, where changes to user data and configurationdata managed by the first storage cluster 602 are backed up to thesecond storage cluster 608 and changes to user data and configurationdata managed by the second storage cluster 608 are backed up to thefirst storage cluster 602. For example, user data and configuration data(e.g., a user access policy 606 specifying that a user (A) has access toa storage object) may be replicated from a first storage virtual machine604 of the first storage cluster 602 to a second storage virtual machine610 of the second storage cluster 608 (e.g., to a replicated user accesspolicy 612 specifying that the user (A) has access to the storageobject), as illustrated in FIG. 6A.

FIG. 6B illustrates a user access modification operation being appliedto the user access policy 606 within the first storage virtual machine604. For example, the user access policy 606 may be modified to specifythat the user (A) now has restricted access to the storage object. Anattempt may be made to replicate/mirror the user access modificationoperation, as configuration mirroring data, from the first storagecluster 602 to the second storage cluster 608 for application to thereplicated user access policy 612. However, the configuration mirroringdata may fail to be applied to the replicated user access policy 612.Thus, if a failover occurs from the first storage cluster 602 to thesecond storage cluster 608 due to a disaster at the first storagecluster 602, the user (A) may have undesirable full access to thestorage object as opposed to the restricted access.

The configuration comparison component 614 may obtain firstconfiguration 632, corresponding to a current state of configurationdata for the first storage virtual machine 604 such as the user accesspolicy 606, from the first storage cluster 602. The configurationcomparison component 614 may obtain second configuration 634,corresponding to a current state of configuration data for the secondstorage virtual machine 610 such as the replicated user access policy612, from the second storage cluster 608. The configuration comparisoncomponent 614 may compare the first configuration 632 and the secondconfiguration 634 to determine a user access policy configurationdifference between the user access policy 606 and the replicated useraccess policy 612 due to the failure to apply the configurationmirroring data to the replicated user access policy 612. Theconfiguration comparison component 614 may provide a notification 636 ofthe user access policy configuration difference, such as through astorage user interface 636.

FIGS. 7A-7B illustrate examples of a system 700, comprising aconfiguration comparison component 714 (e.g., hosted within a firststorage cluster 702, a second storage cluster 708, or another locationor computing device such as an administrator laptop or storage server),for identifying configuration inconsistencies between storage virtualmachine across storage clusters. The first storage cluster 702 and thesecond storage cluster 708 may be configured according to a disasterrecovery configuration, where changes to user data and configurationdata managed by the first storage cluster 702 are backed up to thesecond storage cluster 708 and changes to user data and configurationdata managed by the second storage cluster 708 are backed up to thefirst storage cluster 702. For example, user data and configuration data(e.g., an IP address 706 of 190.80.02.199) may be replicated from afirst storage virtual machine 704 of the first storage cluster 702 to asecond storage virtual machine 710 of the second storage cluster 708(e.g., to a replicated IP address 712 of 190.80.02.199), as illustratedin FIG. 7A.

FIG. 7B illustrates an IP address modification operation being appliedto the IP address 706 within the first storage virtual machine 704. Forexample, the IP address 706 may be modified to a new IP address of111.22.77.65. An attempt may be made to replicate/mirror the IP addressmodification operation, as configuration mirroring data, from the firststorage cluster 702 to the second storage cluster 708 for application tothe replicated IP address 712. However, the configuration mirroring datamay fail to be recorded for the replicated IP address 712. Thus, if afailover occurs from the first storage cluster 702 to the second storagecluster 708 due to a disaster at the first storage cluster 702, usersmay be unable to access applications, user data, databases, and/or othercomponents accessible through the replicated IP address 712.

The configuration comparison component 714 may obtain firstconfiguration 732, corresponding to a current state of configurationdata for the first storage virtual machine 704 such as the IP address706, from the first storage cluster 702. The configuration comparisoncomponent 714 may obtain second configuration 734, corresponding to acurrent state of configuration data for the second storage virtualmachine 710 such as the replicated IP address 712, from the secondstorage cluster 708. The configuration comparison component 714 maycompare the first configuration 732 and the second configuration 734 todetermine an IP address configuration difference between the IP address706 and the replicated IP address 712 due to the failure to record theconfiguration mirroring data for the replicated IP address 712. Theconfiguration comparison component 714 may provide a notification 736 ofthe IP address configuration difference, such as through a storage userinterface 736.

Still another embodiment involves a computer-readable medium comprisingprocessor-executable instructions configured to implement one or more ofthe techniques presented herein. An example embodiment of acomputer-readable medium or a computer-readable device that is devisedin these ways is illustrated in FIG. 8, wherein the implementation 800comprises a computer-readable medium 808, such as a CD-ft DVD-R, flashdrive, a platter of a hard disk drive, etc., on which is encodedcomputer-readable data 806. This computer-readable data 806, such asbinary data comprising at least one of a zero or a one, in turncomprises a set of computer instructions 804 configured to operateaccording to one or more of the principles set forth herein. In someembodiments, the processor-executable computer instructions 804 areconfigured to perform a method 802, such as at least some of theexemplary method 300 of FIG. 3, for example. In some embodiments, theprocessor-executable instructions 804 are configured to implement asystem, such as at least some of the exemplary system 400 of FIGS.4A-4C, at least some of the exemplary system 500 of FIGS. 5A-5B, atleast some of the exemplary system 600 of FIGS. 6A-6B, and/or at leastsome of the exemplary system 700 of FIGS. 7A-7B, for example. Many suchcomputer-readable media are contemplated to operate in accordance withthe techniques presented herein.

It will be appreciated that processes, architectures and/or proceduresdescribed herein can be implemented in hardware, firmware and/orsoftware. It will also be appreciated that the provisions set forthherein may apply to any type of special-purpose computer (e.g., filehost, storage server and/or storage serving appliance) and/orgeneral-purpose computer, including a standalone computer or portionthereof, embodied as or including a storage system. Moreover, theteachings herein can be configured to a variety of storage systemarchitectures including, but not limited to, a network-attached storageenvironment and/or a storage area network and disk assembly directlyattached to a client or host computer. Storage system should thereforebe taken broadly to include such arrangements in addition to anysubsystems configured to perform a storage function and associated withother equipment or systems.

In some embodiments, methods described and/or illustrated in thisdisclosure may be realized in whole or in part on computer-readablemedia. Computer readable media can include processor-executableinstructions configured to implement one or more of the methodspresented herein, and may include any mechanism for storing this datathat can be thereafter read by a computer system. Examples of computerreadable media include (hard) drives (e.g., accessible via networkattached storage (NAS)), Storage Area Networks (SAN), volatile andnon-volatile memory, such as read-only memory (ROM), random-accessmemory (RAM), EEPROM and/or flash memory, CD-ROMs, CD-Rs, CD-RWs, DVDs,cassettes, magnetic tape, magnetic disk storage, optical or non-opticaldata storage devices and/or any other medium which can be used to storedata.

Although the subject matter has been described in language specific tostructural features or methodological acts, it is to be understood thatthe subject matter defined in the appended claims is not necessarilylimited to the specific features or acts described above. Rather, thespecific features and acts described above are disclosed as exampleforms of implementing at least some of the claims.

Various operations of embodiments are provided herein. The order inwhich some or all of the operations are described should not beconstrued to imply that these operations are necessarily orderdependent. Alternative ordering will be appreciated given the benefit ofthis description. Further, it will be understood that not all operationsare necessarily present in each embodiment provided herein. Also, itwill be understood that not all operations are necessary in someembodiments.

Furthermore, the claimed subject matter is implemented as a method,apparatus, or article of manufacture using standard application orengineering techniques to produce software, firmware, hardware, or anycombination thereof to control a computer to implement the disclosedsubject matter. The term “article of manufacture” as used herein isintended to encompass a computer application accessible from anycomputer-readable device, carrier, or media. Of course, manymodifications may be made to this configuration without departing fromthe scope or spirit of the claimed subject matter.

As used in this application, the terms “component”, “module,” “system”,“interface”, and the like are generally intended to refer to acomputer-related entity, either hardware, a combination of hardware andsoftware, software, or software in execution. For example, a componentincludes a process running on a processor, a processor, an object, anexecutable, a thread of execution, an application, or a computer. By wayof illustration, both an application running on a controller and thecontroller can be a component. One or more components residing within aprocess or thread of execution and a component may be localized on onecomputer or distributed between two or more computers.

Moreover, “exemplary” is used herein to mean serving as an example,instance, illustration, etc., and not necessarily as advantageous. Asused in this application, “or” is intended to mean an inclusive “or”rather than an exclusive “or”. In addition, “a” and “an” as used in thisapplication are generally be construed to mean “one or more” unlessspecified otherwise or clear from context to be directed to a singularform. Also, at least one of A and B and/or the like generally means A orB and/or both A and B. Furthermore, to the extent that “includes”,“having”, has, with, or variants thereof are used, such terms areintended to be inclusive in a manner similar to the term “comprising”.

Many modifications may be made to the instant disclosure withoutdeparting from the scope or spirit of the claimed subject matter. Unlessspecified otherwise, “first,” “second,” or the like are not intended toimply a temporal aspect, a spatial aspect, an ordering, etc. Rather,such terms are merely used as identifiers, names, etc. for features,elements, items, etc. For example, a first set of information and asecond set of information generally correspond to set of information Aand set of information B or two different or two identical sets ofinformation or the same set of information.

Also, although the disclosure has been shown and described with respectto one or more implementations, equivalent alterations and modificationswill occur to others skilled in the art based upon a reading andunderstanding of this specification and the annexed drawings. Thedisclosure includes all such modifications and alterations and islimited only by the scope of the following claims. In particular regardto the various functions performed by the above described components(e.g., elements, resources, etc.), the terms used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure. In addition, while aparticular feature of the disclosure may have been disclosed withrespect to only one of several implementations, such feature may becombined with one or more other features of the other implementations asmay be desired and advantageous for any given or particular application.

What is claimed is:
 1. A system for identifying configurationinconsistencies between storage virtual machines across storageclusters, comprising: a processor; and a memory containing instructionswhich when executed by the processor implement at least some of: aconfiguration comparison component configured to: evaluate a firststorage virtual machine within a first storage cluster to identify afirst configuration of the first storage virtual machine; evaluate asecond storage virtual machine within a second storage cluster toidentify a second configuration of a second storage virtual machinehaving a replication relationship with the first storage virtualmachine; compare the first configuration and the second configuration todetermine whether there is a configuration difference between the firststorage virtual machine and the second storage virtual machine; andresponsive to determining the configuration difference, provide anotification of the configuration difference.
 2. The system of claim 1,the configuration comparison component configured to: compare at leastone of volume information, snapshot policies, network interfaces,routing routes, internet protocol (IP) information, storage objectinformation, user access policies, or storage configuration policiesbetween the first configuration and the second configuration.
 3. Thesystem of claim 1, the configuration comparison component configured to:specify, through the notification, that the configuration differenceresulted based upon a failure to record configuration mirroring datasent from the first storage cluster to the second storage cluster forapplying to the second storage virtual machine.
 4. The system of claim1, the configuration comparison component configured to: specify,through the notification, that the configuration difference resultedbased upon a failure to transfer configuration mirroring data from thefirst storage cluster to the second storage cluster for applying to thesecond storage virtual machine.
 5. The system of claim 1, theconfiguration comparison component configured to: specify, through thenotification, that the configuration difference resulted based upon afailure to apply configuration mirroring data, sent from the firststorage cluster to the second storage cluster, to the second storagevirtual machine.
 6. The system of claim 1, the configuration comparisoncomponent configured to: specify, through the notification, that atleast one of volume information, snapshot policy information, networkinterface information, routing route information, internet protocol (IP)information, storage object information, user access policy information,or storage configuration policy information is different between thefirst configuration and the second configuration.
 7. The system of claim1, the configuration comparison component configured to: perform thecomparison in real-time during at least one of operation of the firststorage cluster and the second storage cluster or replication of userdata and configuration data from the first storage cluster to the secondstorage cluster.
 8. The system of claim 7, the replication comprising asynchronous replication operation that transfers the configuration datato the second storage cluster for application to the second storagevirtual machine in real-time.
 9. The system of claim 7, the replicationcomprising an asynchronous replication operation.
 10. The system ofclaim 1, the first storage cluster and the second storage clusterconfigured according to a disaster recovery configuration.
 11. Thesystem of claim 10, the second storage cluster configured to providefailover client access to the second storage virtual machine, based uponthe disaster recovery configuration, responsive to a disaster occurringat the first storage cluster that renders the first storage virtualmachine inaccessible to clients.
 12. The system of claim 11, the secondstorage cluster configured to switch back to the first storage clusterfor primary client access to the first storage virtual machine, basedupon the disaster recovery configuration, responsive to the firststorage cluster recovering from the disaster.
 13. The system of claim11, the first storage virtual machine configured for primary clientaccess and the second storage virtual machine configured as a backupstorage virtual machine for failover client access when the firststorage virtual machine is inaccessible for primary client access.
 14. Amethod for identifying configuration inconsistencies between storagevirtual machines across storage clusters, comprising: evaluating a firststorage virtual machine within a first storage cluster to identify afirst configuration of the first storage virtual machine; evaluating asecond storage virtual machine within a second storage cluster toidentify a second configuration of a second storage virtual machinehaving a replication relationship with the first storage virtualmachine; comparing the first configuration and the second configurationto determine whether there is a configuration difference between thefirst storage virtual machine and the second storage virtual machine;and responsive to determining the configuration difference, providing anotification of the configuration difference.
 15. The method of claim14, comprising: specifying, through the notification, that theconfiguration difference resulted based upon a failure to recordconfiguration mirroring data sent from the first storage cluster to thesecond storage cluster for applying to the second storage virtualmachine.
 16. The method of claim 14, comprising: specifying, through thenotification, that the configuration difference resulted based upon afailure to transfer configuration mirroring data from the first storagecluster to the second storage cluster for applying to the second storagevirtual machine.
 17. The method of claim 14, comprising: specifying,through the notification, that the configuration difference resultedbased upon a failure to apply configuration mirroring data, sent fromthe first storage cluster to the second storage cluster, to the secondstorage virtual machine.
 18. The method of claim 14, comprising:specifying, through the notification, that at least one of volumeinformation, snapshot policy information, network interface information,routing route information, internet protocol (IP) information, storageobject information, user access policy information, or storageconfiguration policy information is different between the firstconfiguration and the second configuration.
 19. The method of claim 14,the comparing comprising: comparing the first configuration and thesecond configuration in real-time during at least one of operation ofthe first storage cluster and the second storage cluster or replicationof user data and configuration data from the first storage cluster tothe second storage cluster.
 20. A computer readable medium comprisinginstructions which when executed perform a method for identifyingconfiguration inconsistencies between storage virtual machines acrossstorage clusters, comprising: evaluating a first storage virtual machinewithin a first storage cluster to identify a first configuration of thefirst storage virtual machine; evaluating a second storage virtualmachine within a second storage cluster to identify a secondconfiguration of a second storage virtual machine having a replicationrelationship with the first storage virtual machine, the second storagecluster configured to provide failover client access to the secondstorage virtual machine based upon a disaster recovery configurationresponsive to a disaster occurring at the first storage cluster thatrenders the first storage virtual machine inaccessible to clients;comparing the first configuration and the second configuration todetermine whether there is a configuration difference between the firststorage virtual machine and the second storage virtual machine; andresponsive to determining the configuration difference, providing anotification of the configuration difference.